Load transfer dolly

ABSTRACT

Axle vehicle loads are transferred or equalized utilizing a wheeled dolly to create a variable wheelbase which is adapted to be moved from a retracted position on the basic vehicle frame to a maximum outward position. The axle and wheels of the load transfer dolly are pivoted from an inoperative, above-the-road position downwardly to engagement with the road and, by the application of additional pressure, will take up a portion of the load of the vehicle.

United States Patent 1151 3,685,853 Goldsmith 1451 Aug. 22, 1972 1541 LOAD. TRANSFER DOLLY 3,191,963 6/1965 9118111110,, ..180/79.2 x I Z I 2,433,268 12/1947 Fellabaum ..280/81ux 1 f Aves Gdds'mthTulsa Okla 3,442,409 5/1969 Larson ..280/81 x [73] Ass1gnee: CCI Corporation, Tulsa, Okla. 3,101,958 8/1963 Gerou ..280/81 X [22] Filed: Jam 16, 1970 2,848,244 8/1958 Georg1...' ..280/81 A [21] Appl. No.: 3,404 Primary Examiner-Benjamin Hersh Assistant Examiner-John P. Silverstrim 52 US. Cl ..280/81 R, 280/34 A, 280/43.23, &

280/109, 280/112, 280/l50.5, 280/150 A, TR 4 280/405A [57] ABS CT 51 .1111. Cl. ..B60s 9/00, 860p 3/16 Axle vehwle loads are transferred or equahzed [58] Field ofSearch....280/8l R, 81 A, 481 B, 43.23, a wheeled. dolly recreate a variable wheelbase [56] References Cited position. The axle and wheels of the load transfer dolly are pivoted from an inoperative, above-the-road UNITED STATES PATENTS position downwardly to engagement with the road- 1 and, by the application of additional pressure, will 1 23:22:3 take up a portion of the'load of the vehicle. 2,490,014 12/ 1949 Brand ..280/34 X 6 Claims, 8 Drawing figures '1 46 2 I I 4) \k H I, 50 ,8 3. A\\\\\ m 4 C 62 FORWARD I} 38 40 v" l 3 f 1 42 x a U I 26 1 "1% 24 \B I! b 35 J I8 22 44 I *3: I" \IS which is adapted to be movedfrom a retracted position on the basic vehicle frame to a maximum outward PATEN'TED M1922 I972 sum 1 or 5 xsk .T RI mw mm VO N6 s a? E M ATTORNEYS P'ATENTED M1822 I972 SHEEI 2 0F 5 INVENTOR. AVE 5. GOLDSMITH A TTOR/VE Y5 PATENTEU I972 3,685,853

sum 3 or 5 INVENTOR.

AVE 5. GOLDSMITH BY I A T TOR/VFYS LOAD TRANSFER DOLLY BACKGROUND OF THE INVENTION This invention pertains to the field of land vehicles and, more particularly, to a device for attachment to an existing vehicle frame, as for example, that of a conventional transit mixer or other type of load carrying vehicles.

PRIOR ART 3,l9l,96l Brennan, et al. 3,l9l,963Pritchard 3,246,884-Pritchard, et al. 3,298,706-Lyall 3,3 l 7,193Buelow, et al.

2,902,289-North 2,974,976-Lyall 3,038,704-Cook 3,1l2,l-Pritchard 3,156,484-Talbert 3,l61,4l 8-Brennan, et al.

SUMMARY The invention provides an auxiliary wheeled dolly for a vehicle which provides a variety of use situations including, but not limited to, being positionable in a number of positions varying from fully retracted to fully extended relative to the frame of the vehicle; said dolly also being pivotal to provide a desired pressure force between the wheels and the frame to shift or equalize the load on one or more fixed axles of said vehicle; and being also positionable in a fixed, nonsteerable or tag axle relationship to the vehicle as a safety means in backing up or where the vehicle is operating on a steep grade.

This invention further provides a device for equalizing and transferring axle loads which can be quickly and completely disconnected from the main vehicle for service and maintenance without causing down time of the vehicle. A further object of this invention is to provide apparatus that is applicable to other vehicles than mixer carriers, e.g., vehicles for hauling concrete blocks or bricks and, as such, is a device which will not interfere with loading or unloading of materials on the vehicle.

A yet further object of this invention is to provide a bearing type fifth wheel arrangement between the load transfer dolly and the vehicle frame which permits improved tracking of the dolly and eliminates wheel wobble found in caster-type wheels. The load transfer device of this invention laterally oscillates with undulations in the road while maintaining adjustable lateral stability. In addition, the device of this invention is capable of movement inward or outward from the vehicle frame and thereby will change the location of the trailing axle behind the vehicle for different leverage conditions and, in some instances, without changing hydraulic load conditions. This invention further provides an improved hydraulic system for operating the load transfer device and which allows application of desired axial load conditions on all wheels of the vehicle.

These and other objects of the invention, as improvements over that known in the art heretofore, will become more apparent upon further reading of the specification and claims, taken in conjunction with the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top elevational view showing'the rear portion of a vehicle carrier and the load transfer dolly of this invention in an extended position. I

FIG. 2 is a side elevational view of that portion shown in FIG. 1.

FIG. 3 is a partial side elevational view showing the load transfer dolly of this invention in its retracted position.

FIG. 4 is an end view depicting the load transfer dolly of this invention in a laterally oscillated position.

FIG. 5 is a partial sectional view depicting the latching mechanism to retain the dolly to the basic vehicle frame.

FIG. 6 is a partial top view of an embodiment depicting means to restrict the tracking oscillation of the dolly FIG. 7 is a frontal view of the restriction plate shown in FIG. 6. I

FIG. 8 is a schematic drawing of the hydraulic system used in conjunction with the load transfer dolly of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Before describing the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

For the purpose of simplification the drawings show only the rear portion of a typical vehicle or fifth wheel mounted carrier frame 10 which may have one or more fixed rear wheeled axles generally designated by the numeral 12 and one or more forward wheeled axles, not shown. The frame may include one or more cross braces as at 14. The load transfer dolly of this invention is generally designated by the numeral 16 and includes parallel frame members 18 supported by a forward cross member 20 and a rearward cross member 22. A first hydraulic cylinder 24 is attached at its cylinder end to the vehicle frame cross member 14 while the rod end 26 is attached to the rearward cross member 22 of the transfer dolly of this invention. The frame members 18 are adaptable to slide forwardly and rearwardly upon an appropriate track 11 within the frame 10 from a position such as shown in FIG. 3 outwardly to a position as shown in FIGS. 1 and 2 by actuation of the hydraulic cylinder and rod 24 and 26. The dolly frame assembly 18 includes downwardly extending arms 28 which are adapted to support a first axis or shaft 30 which is horizontal and transverse to the frame 18 and extends through a type of fifth wheel assembly generally designated by the numeral 32. The assembly 32 pivots about shaft 30 in a vertical plane from and between a retracted position as shown in FIG. 3 to a position where the dolly wheels 46 are in ground or road and load force engaging position. The assembly 32 includes an upper mounting plate 34 interconnected to a lowerv mounting plate 36 by a bearing assembly 35 which permits relative, fifth wheel like rotation of lower mounting frame 36 to upper mounting bracket 34 about an imaginary second axis which is in a plane transverse to said first axis. This relative movement allows the lower frame assembly and the wheeled axle 44 to freely pivot and trail the vehicle within the limits described hereafter in reference to FIGS. 6 and 7.

' Pivotation of the assembly 32 occurs utilizing hydraulic or pneumatic cylinder 38 which is attached at one end to the cross frame 20 while the piston rod 40 is pivotally attached to the upper mounting plate 34 about shaft42. The lower mounting frame member 36 includes axle 44 having spaced wheels 46 rotatably supported, in the load transfer position, on the ground or road surface. A rear protecting bumper 48 maybe utilized in addition to other auxiliary equipment, not shown, such as fenders and mud flaps. As best described in FIG. 4, the axle 44 is further pivoted about a third axis generally parallel with the forward-rearward axis of the load transfer dolly by the provision of shaft 50 which interconnects the axle 44 to the lower support frame 36. This connection, permits limited movement in a plane transverse to the forward-rearward axis for irregular surfaces such as described in FIG. 4. Resilient bumper members 52 are provided between the lower frame 36 and the axle 44 and act as a shock absorbing means and are mounted to provide adjustable means for greater or less resistance to the oscillatory movement of the axle 44.

A latch mechanism includes a portion 60 fixed to the end of vehicle frame and a pivotal latch 62 attached to the dolly assembly 32. The latch 62 is biased by a spring 64 normally forward. The latch is adapted to be used when the transfer dolly 16 is pivoted upwardly in its non-use position. The partial view of FIG. 5 depic the latched position. I

Referring now'to FIG. 6, an additional embodiment of this invention is described. In normal operation of the load transfer dolly, the bearing assembly 35 is fixed in its pivotal movement to about each side of the forward-rearward axis by the relationship of a tongue the dolly extension frame 16 is retracted forwardly within the frame 10 and generally to that position shown in FIG. 3. As such, the pivotal latch 62 retains the weight of the axle 44 and wheels 46 such as shown in FIG. 5. When it is desired to use the load transfer dolly, suitable controls located within the vehicle operator compartment are actuated. The dolly is first extended to its outer position, which may be any position between fully retracted and fully extended. This is accomplished hydraulically by a pump 90 which may be either a separate power take-off driven pump or may be readily combined with an available power source. such as the power steering system of the vehicle. A

' common tank or reservoir 92 will contain the liquid and, although schematically shown in other portions of the drawing, it may be considered as a common reservoir. Fluid traverses through line 94 into a four-way solenoid-operated valve 96 which the operator has positioned to allow flow of hydraulic pressure fluid through line 98, through double check valve 100, into 66 which is affixed to the upper mounting plate 34 of the bearing assembly 35. Plate 72, as best shown in FIG. 7, is formed with openings 74 and 76 at each end v for adaptation about pins 78 and 80 being retained by lock pins 82 and 84. Pins 78 and 80 are rigidly formed to the lower mounting plate 36. Hence, plate 72 pivots relative to the upper mounting plate as shown by the dotted lines of FIG. 6. However, it is to be understood 1 that the mechanism is reversible, i.e., tongue 66 fixed to lower mounting plate 36 while the restriction plate 72 isaffixed to the upper mounting plate 34. The plate 72 isreversible wherein the edge 86 is placed so that operations the plate is then reversed with edge 71 terthe piston side of cylinder 24 forcing the rod 26 and the dolly frame outward to a position as for example shown in FIGS. 1 and 2. Fluid on the rod side of the cylinder 24 is allowed to flow through conduit 102, because of a pilot crossover arrangement within the double check valve 100, back through the four-way valve 96, through conduits 104 and 106, thence through two-way valve and check 108, conduit 107 and normally open dump valve 110 to the reservoir 92. Once the desired extended position is reached, the four-way valve is closed trapping the hydraulic pressure fluids in the extension system. As the dolly is being extended, the latch 62 will ride upon the upper surface of fixed latch 60'until free thereof at which time the load transfer dolly will pivot about shaft 30 to the ground. The dolly will fall slowly because of a flow control restriction l 12, thefluid flowing from the rod 40 side of load cylinder 38 through conduits 104, 106 and 107 to thereservoir. To apply load transfer force, once the required position is reached, the dump valve 1 10 is closed to allow pressure fluid through lines 94, 104, 106, two-way valve and check 108, line 114 to a hydraulic accumulator 116 and via conduit 118 to the piston side of cylinder 38.

Flow also enters pilot conduit 120 which is used to actuate, upon desired pressure conditions, unloading valve 122. The amount of pressure in conduit 114 and accumulator 116 will, of course, depend upon the amount of load being carried by the vehicle or carrier and upon the desired transfer or equalization of axle load between the' vehicle wheels. The'desired amount rod side of the load cylinder 38 allowing the application of desired pressure forces to the piston side and hence the dolly wheels. In this condition as the vehicle is allowed to traverse over the ground surface irregularities are constantly transferred from the wheels 46 and axle 44 into the load cylinder piston via rod 40. As such, the load cylinder must be adaptable to accept and withdraw fluid on either side of the piston and act as a dampening means to the variations in the road traveled. This is accomplished on the rod side by maintaining a constant source of low pressure fluid operating through conduits 104 and 111 through the flow control bypass 112. On the piston side this is accomplished by the constant tendency when the pressure is lessened to pump further fluid through conduits 104, 106, two-way valve and check 108 and conduit 114 in the event there is a sudden change in the load cylinder piston as for example when the wheels 46 fall into a depression in the ground or road surface. Pressure surges on the piston side of cylinder 38 are normally dampened by accumulator 116. Relief valve 111 is set to relieve excessive pressure surges in conduits 114 and 107 as may be caused when axle 44 is traversing severe irregularities in the road.

For changes in the load condition, e.g., removal of a portion of the pay load, the dolly forces may be easily redistributed. In one method, the operator first opens dump valve 110. The four-way valve 96 is actuated to retract the extension frame 18 to a predetermined position corresponding to the pay load. Dump valve 110 is then closed and the dolly axle 44 is repressurized.

In another method the pressure setting of unloading valve 122 is changed corresponding to the new pay load. If the vehicle has removed its load the dolly is fully retracted and latched as shown in FIGS. 3 and 5.

Although this invention has been described with reference to specific and preferred embodiments, it is understood that various changes may be made in its construction by those skilled in the art without departing from the spirit of the invention as defined in the appended claims.

What is claimed:

1. A dolly to increase the wheeled, load carrying capacity of a given vehicle comprising:

an extensible frame movable rearwardly and forwardly upon the rear end frame of said vehicle; means to move said extensible frame from or to a position substantially beneath said rear end frame rearwardly to a desired position; an axle having wheels on the ends thereof spaced about the same track as said vehicle wheels, said axle mounted to said extensible frame so as to pivot relative thereto: 1. about a first horizontal transverse axis; and 2. about a second axis which is in a transverse plane to said first axis whereby said wheeled axle trails with said vehicle; and 3. about a third axis substantially parallel to the forward-rearward axis of said extensible frame, whereby said wheeled axle pivots in a transverse plane to said extensible frame; and means to controllably pivot said wheeled axle about said first horizontal transverse axis from and between a position where said wheels are off the 0 nd toa osition on the round. 2. A iiolly 0 claim 1 wher%in said wheeled axle mounting comprises:

an upper mounting plate pivotally movable about said first axis;

a lower mounting plate rotatably supported to said upper mounting plate about said second axis; and means to rotatably support said axle to said lower mounting plate about said third axis.

3. A dolly of claim 1 including means to releasably latch said wheeled axle to said vehicle frame in said above-the-ground position.

4. A dolly according to claim 2 including means to limit the relative side to side rotation of said lower and upper mounting plates.

5. A dolly according to claim 4 including means to lock said lower mounting plate to said upper mounting plate in a fixed position.

6. A dolly in accord with claim 1 including resilient bumper members positioned between said extension frame and said axle to restrict the rotatable movement of said axle about said third axis. 

1. A dolly to increase the wheeled, load carrying capacity of a given vehicle comprising: an extensible frame movable rearwardly and forwardly upon the rear end frame of said vehicle; means to move said extensible frame from or to a position substantially beneath said rear end frame rearwardly to a desired position; an axle having wheels on the ends thereof spaced about the same track as said vehicle wheels, said axle mounted to said extensible frame so as to pivot relative thereto:
 1. about a first horizontal transverse axis; and
 2. about a second axis which is in a transverse plane to said first axis whereby said wheeled axle trails with said vehicle; and
 3. about a third axis substantially parallel to the forwardrearward axis of said extensible frame, whereby said wheeled axle pivots in a transverse plane to said extensible frame; and means to controllably pivot said wheeled axle about said first horizontal transverse axis from and between a position where said wheels are off the ground to a position on the ground.
 2. about a second axis which is in a transverse plane to said first axis whereby said wheeled axle trails with said vehicle; and
 2. A dolly of claim 1 wherein said wheeled axle mounting comprises: an upper mounting plate pivotally movable about said first axis; a lower mounting plate rotatably supported to said upper mounting plate about said second axis; and means to rotatably support said axle to said lower mounting plate about said third axis.
 3. A dolly of claim 1 including means to releasably latch said wheeled axle to said vehicle frame in said above-the-ground position.
 3. about a third axis substantially parallel to the forward-rearward axis of said extensible frame, whereby said wheeled axle pivots in a transverse plane to said extensible frame; and means to controllably pivot said wheeled axle about said first horizontal transverse axis from and between a position where said wheels are off the ground to a position on the ground.
 4. A dolly according to claim 2 including means to limit the relative side to side rotation of said lower and upper mounting plates.
 5. A dolly according to claim 4 including means to lock said lower mounting plate to said upper mounting plate in a fixed position.
 6. A dolly in accord with claim 1 including resilient bumper members positioned between said extension frame and said axle to restrict the rotatable movement of said axle about said third axis. 